Apparatus for high-temperature uses



UNITED STATES FRANK A. FAHRENWALD, OF CLEVELAND HEIGHTS, OHIO.

APPARATUS FOR HIGH IEMPERATURE USES.

Specification of Letters Patent. Patented 24 1 2 No Drawing. Application filed August 25, 1919, Serial No. 319,755.- Renewed October 4, 1920. Seri l No. 414,617. v

To mll'whom it may concern:

Be it known that, I, FRANK A. FAHREN- WALD, a citizen of the United States, residing at Cleveland Heights, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Apparatus for High-Temperature Uses, of which the following is a full, clear, and exact description.

This invention relates to alloys and has for its especial object the provision of an inexpensive and mechanically strong com position of matter which shall withstand repeated exposure to high temperatures without material oxidation, disintegration or change of shape. A great need exists for such an alloy in the manufacture of heat treating boxes; carbonizing boxes; leadpots; furnace parts, retorts for the distillation of wood, coal oil and oil bearing shalcs; containers for the production of calcium cyanamid; doors; chains; links and rabblearms for'metallurgical furnaces; and many other metallurgical and chemical relations.

Also such alloys in case they have therequisite hardness are of great value for cutting tools and tools for working hot metal. All the foregoing uses are grouped under the expression apparatus for high temperature uses.

The essential desiderata of such apparatus are cheapness and availability, coupled with reasonably long life. Containers, boxes, and some other articles have been made from certain alloys of nickel and chromium, and serve very effectually the uses to which they are put but their expensiveness is absolutely prohibitive for most purposes, and the same is true of most other compositions heretofore proposed for such uses. The object of my invention is to secure a sufliciently resistant alloy for most practical purposes with the use of inexpensive ingredients and without requiring ex pensive processes of manufacturing.

Although special substances may be added for special purposes as hereinafter set forth my improved apparatus is ordinarily made' from an alloy containing essentially the following ingredients, (the first column showing the preferred species and the second column the permissible variations):

Per cent. Per cent. Iron 80 -85) Chromium 15 10 -20) Silicon 2. 5 2 6) Carbon r 1' 2 2) Manganese .5 .5- 1) Aluminum 5 1- 5) Titanium 5 2 2- 1) The iron constitutes the base of the alloy and g ves the necessary cheapness. The chromium affords a large amount of resistance to oxidation at high temperatures together with bringing into solution the remainlng ingredients and reducing the em- .brittling tendency of the silicon. The carbon occurs largely as an impurity, although It has the effect of increasing greatly the hardness when cold and reducing the plasticity when hot while assisting in the casting operation by increasing fluidity when molten. The manganese acts as a scavenger particularly of oxygen and sulfur; the tita- -n1um acts as a scavenger of oxygen and nitrotime in any one alloy except as pointed outv in the clalms hereto annexed. The essential substances are the iron, chromium, silicon and carbon although I ordinarily employ at least one and sometimes two or three of the remaining ingredients because of the minor improvement produced by their spe' cific effect above mentioned.

This alloy is almost non-magnetic and hence is peculiarly available in many electrical devices such as electric and induction furnaces. It is very strong, both hot and cold, and will withstand a temperature of 1000 C. almost indefinitely.

This alloy can be produced by a great many different processes and owing to the permissible elasticity of its composition eX- treme care need not be used. The nonferrous elements are combined and employed so as to neutralize each others baneful physical effects while augmenting each others chemical effects. The loy is preferably made by adding ferro-chrome to a bath of molten iron in an electric furnace, and also adjusting the amounts of the minor ingredients depending upon the amounts of the same already present as impurities in the iron and ferrochrome. It can also be made by melting together the pure materials in an electric or other furnace or by reducing the essential elements from the ore as descr1bed and claimed in my Patent No. 13%,187, issued of silicon, combined with smaller amounts of carbon and manganese.

2. Apparatus for high temperature uses made from an alloy comprising a large preponderance of iron together with about 10% to 20% of chromium and about 2% to 6% of silicon, combined with smaller amounts of carbon, manganese, aluminum, and titanium.

3. Apparatus for high temperature uses made from an alloy comprising a large preponderance of iron together with about 10 to 20% of chromium and about 2% to 6% of silicon, combined with smaller amounts of at, least two of the substances carbon, manganese, aluminum and titanium.

41. Apparatus for high temperature uses made from an alloy comprising a large preponderance of iron together with about 10% to 20% of chromium and about 1% to 8% of a tungsten-like metal, combined with about 2% to 6% of silicon. a small amount of carbon, and fractional percentages of manganese and titanium.

5. Apparatus for high temperature uses consisting substantially of 75% to 85% of iron, 10% to 20% of chromium, 2% to 6% of silicon, 5% to 1% of each of the metals manganese and titanium, and 2% to 2% of carbon.

In testimony whereof, I hereunto ah'ix my signature.

FRANK A. FAHRENVALD. 

